Coarctation of the Aorta

A 35 year old woman presents to the cardiology clinic with a five year history of hypertension requiring three antihypertensive medications. She reports persistent headaches, dizziness, and exertional dyspnea over several years. There is no family history of cardiovascular disease. On examination, blood pressure is 180/100 mm Hg in the right arm, while blood pressure in the lower extremities is reduced. Pulse rate is 88 per minute. Radial pulses are strong and brisk, whereas femoral pulses are weak and delayed, consistent with radiofemoral delay. Electrocardiography shows left ventricular hypertrophy. Chest X ray demonstrates bilateral rib notching and a focal indentation of the distal aortic arch consistent with the figure 3 sign. Echocardiography confirms LVH. Routine laboratory investigations and abdominal ultrasound are normal. Diagnosis?

Diagnosis is Coarctation of the Aorta.

1. Definition

Coarctation of the aorta is a congenital narrowing of the aorta, most commonly located just distal to the left subclavian artery near the ductus arteriosus in the juxtaductal region. It results in upper body hypertension and reduced lower body perfusion.

2. Etiology and Associations

2.1 Congenital

1. Juxtaductal narrowing of the aorta
2. May remain asymptomatic until adulthood

2.2 Common Associations

1. Bicuspid aortic valve
2. Turner syndrome
3. Berry aneurysms of the circle of Willis

3. Pathophysiology

3.1 Core Mechanism

1. Aortic narrowing increases afterload
2. Leads to left ventricular pressure overload
3. Causes left ventricular hypertrophy

3.2 Hemodynamic Effects

1. Proximal hypertension
2. Distal hypoperfusion
3. Activation of the renin angiotensin aldosterone system (RAAS) due to reduced renal perfusion

3.3 Collateral Circulation

1. Development of intercostal collateral vessels
2. Leads to rib notching

4. Clinical Features

4.1 Core Features

1. Resistant hypertension in a young patient
2. Headache and dizziness
3. Exertional dyspnea

4.2 Vascular Findings

1. Upper extremity BP > lower extremity BP
2. Radiofemoral delay
3. Weak femoral pulses

4.3 Additional Findings

1. Lower limb claudication
2. Systolic murmur best heard over the interscapular region

5. Diagnostic Evaluation

5.1 Chest X ray

1. Rib notching
2. Figure 3 sign

5.2 Electrocardiography

1. Left ventricular hypertrophy

5.3 Echocardiography

1. Assesses LVH
2. May have limited visualization of coarctation in adults, but is useful for identifying associated cardiac abnormalities

5.4 CT Angiography or Cardiac MRI

1. Preferred imaging modality in adults
2. Defines location, severity, and collateral circulation

6. Hemodynamic Profile

1. Upper limb hypertension
2. Lower limb hypotension
3. Pressure gradient > 20 mm Hg

7. Complications

1. Aortic dissection or rupture
2. Intracranial hemorrhage due to berry aneurysm
3. Heart failure
4. Premature coronary artery disease
5. Persistent hypertension after repair

8. Management

8.1 Indications

1. Pressure gradient > 20 mm Hg
2. Hypertension
3. Left ventricular hypertrophy

8.2 Definitive Treatment

1. Endovascular stent placement preferred in adults
2. Surgical repair with resection and anastomosis

8.3 Long Term Care

1. Lifelong follow up
2. Monitor for persistent hypertension
3. Risk of recoarctation and aneurysm formation

9. Key Clinical Insight

Resistant hypertension + radiofemoral delay + rib notching = coarctation of the aorta

10. Exam Level Pearls

1. Upper limb hypertension with lower limb hypotension is classic
2. Rib notching indicates collateral circulation
3. Bicuspid aortic valve is a common association
4. CT angiography is preferred in adults
5. Hypertension may persist even after repair